1. Field of the Invention
This invention relates to refrigerator cabinet assemblies and, in particular, to means for preventing air transfer between different compartments of a refrigerated space defined by a divider wall.
2. Description of the Background Art
In one conventional form of refrigeration apparatus, an insulated cabinet is defined by an outer shell and an inner liner, with insulation, such as foamed-in-place insulation, therebetween. The cabinet defines a space to be refrigerated, with an access opening thereto selectively closed by a door.
In one conventional form of such apparatus, the space is divided into a below-freezing compartment and an above-freezing compartment by a separator wall. The separator wall is retained in the cabinet by a center rail which extends across the access opening. In such a divided compartment refrigeration cabinet structure, a separate door is provided for access selectively to the below-freezing space and above-freezing space. Each of the doors is conventionally carried on pivot hinges, one of the hinges mounted to the cabinet and the other conventionally mounted to the center rail.
The center rail includes end portions which overlap the front edge of the cabinet outwardly of the access opening.
In one form of cabinet construction, the separator wall is received in channels formed in the liner extending rearwardly from the access opening to the rear of the cabinet space.
The center rail normally is covered by a metal cover for aesthetic purposes and for sealing engagement with a magnetic door gasket. Thus, a number of metal surfaces are exposed at the front of the cabinet on which condensation may form and through which heat may enter the refrigerated spaces. It is desirable to eliminate movement of refrigerated air from one refrigerated compartment to the other along a path that would bring the air in contact with the exposed metal surfaces, or in contact with metal parts that are in heat transfer association with exposed metal surfaces, so as to maximize energy consumption efficiency in the operation of the apparatus.
It has been found that because of manufacturing tolerances and the inherent characteristics of such refrigerator cabinet design, a number of air leakage paths may exist between the compartments through which air may migrate from one compartment to the other, particularly under pressure differences, such as introduced by the use of the evaporator fan. Air movement may further occur because of the difference in temperatures between the two compartments. Illustratively, the below-freezing compartment is maintained at approximately 0.degree. F. and the above-freezing temperature compartment may be maintained at approximately 32.degree. F. or more.
The use of seals to prevent air migration between compartments defined by a separator wall in a refrigeration apparatus is known in the art. For example, in U.S. Pat. No. 4,191,434 of John M. Powell et al. a flexible, resilient sealing member 28 is provided along the entire three sides of a separator wall that contact the cabinet liner, to prevent inter-compartment air movement across the sides of the separator wall. The present invention, however, recognizes that such air movement across the sides of the separator wall is not harmful as long as it is not excessive. In fact, such a conventional refrigeration apparatus typically has only one evaporator, located in the below-freezing compartment, and provides ducts and baffles to effect an orderly exchange of refrigerated air between compartments to refrigerate the above-freezing compartment.
The present invention teaches, however, that movement of refrigerated air between compartments will result in a loss of energy consumption efficiency and excessive external condensation formation when the movement occurs along paths that allow the air to flow across metal members which form portions of the outer metal cabinet shell. The moving air extracts a large amount of heat from even a small area of metal with which it comes in contact. This heat enters the refrigerator cabinet and must be extracted by the refrigeration compressor. This flow of heat also causes localized external cold spots that must be heated by anti-sweat heaters, which consume electrical energy and further add undesirable heat to the cabinet, contributing to a lower operating efficiency.